Hi everyone
I'm new to this forum and I need some expert help on a color organ that I've been trying to make.
The color organ that I need will have a microphone input (as opposed to a direct connection to a speaker), and will only have a low-pass filter.
Some details: The input voltage must be 12V DC 2000mA. The output can be 12V.
The color organ will drive one of these: http://www.superbrightleds.com/specs/FLB.htm

The LED will only switch on. I do not need the intensity to change.
Is it possible to use a potentiometer to vary the frequency between around 80Hz to 150Hz? If not, around 100 Hz should be OK.
Thank you!

You are right. In the preamp you can change the gain as needed with a resistor.
The lower part of the other picture is indeed the lowpass filter.
On the bottom of the page there is a list of frequentions given.